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72 2174 4 Asbestos 1972 environmental protection monograph series ASBESTOS PLAINTIFF'S EXHIBIT DOW-1045 am M M0UND CXI FEB 1 91987 PREPARED BY ECOLOGY COUNCIL TASK FORCE THE DOW CHEMICAL COMPANY March 1972 2 z s 7 ^' 4 68Q0Q01S DOW CONFIDENTIAL DO NOT COPY. GET CURRENT COPY FROM DOW ECOLOGY COUNCIL RECEIVED MAR 16 1972 CXI MIDLAND * Asbestos 1972 - A1 ENVIRONMENTAL PROTECTION MONOGRAPH SERIES ASBESTOS A) THE CHEMISTRY OF ASBESTOS Geologists recognize more than thirty asbestiform minerals. How ever, only six of these are used commercially, namely, chrysotile, amosite, anthophyllite, crocidolite, tremolite and actinolite. Of these, chrysotile accounts for 96% of the asbestos consumed; amosite, 2%; crocidolite, 2%; and the other three total less than 1%. Chemical formulas for these forms of asbestos are given below: Type Chemical Formula Chrysotile (Serpentine group) Mg^S^O^ (OH) ^ ST0000892 Amosite (Amphibole group) (Fe,Mg)7Sig022(OH)2 Anthophyllite (Amphibole group)(Fe,Mg)7Sig022(OH)2 Crocidolite (Amphibole group) Na2(Fe+2,Mg)3Fe23Sig022(OH)^ Tremolite (Amphibole group) Ca2Mg5Sig022(OH)2 Actinolite (Amphibole group) Ca2(Mg,Fe)sSig022(OH)^ Since chrysotile is by far the most important and widespread form of asbestos, it will be described in some detail. A typical analysis of chrysotile is the following: MgO Si02 AI5O3 Feo Fe203 C02 Loss on Ignition 40.6 39.S 0.7 1.3 2.3 0.5 14.0 In addition the mineral usually contains trace amounts of other metals and up to 0.21 organic carbon in the form of oils. Asbestos 1972 - A2 Chrysotile is a fibrous mineral. It is made up of layers of silicon- oxygen tetrahedra condensed onto magnesium hydroxide. The combined silica-magnesium hydroxide network is put together in a manner such that curved sheets 7.3 Angstroms (A) in thick ness are formed with the outside (convex) surface always contain ing OH groups. Twelve to twenty such sheets are mechanically bound together in such a way that round, hollow fibers are produced. The fiber diameter (180-25CA) is several orders of magnitude smaller than cotton or wool fibers. The fibers may be very short (a few hundred Angstroms) or up to three inches in length. Normally, many fibers are bound together forming bundle#'? up to 0.03" in diameter. H However, it must be borne in mind thatO CD asbestos samples may contain dust particles as small as 200 A byg 200 A. CD co Chrysotile is quite resistant to alkali, but is attacked by aqueous HC1, possibly because the outside surface of the fiber is largely Mg(OH)j When slurried with water enough hydrolysis occur# to produce a pH of about 10, which is also characteristic of Mg(OH)2 in water. The surface of an asbestos fiber in water is positively charged due to loss of OH", but the addition of base reduces this charge to zero near pH 12. At low pH (around 3) Mg4 2 are also lost from the surface reducing the surface charge and exposing Si02 to the solution. Strong acids (e.g. 1 N HCl at 95C. for one hour) completely dissolves away the Mg(OH)2 from the mineral leaving behind amorphous Si(>2 in a fragile fibrous morphology. Asbestos is stable in air and water, and would be Asbestos 1972 - A3 expected to persist in the natural environment. Chrysotile loses its water of hydration at about 450C., and can be dehydroxylated at 650*C. t ST000089U Asbestos 1972 - B1 B) OCCURRENCE OF ASBESTOS 1) Natural Occurrence of Asbestos - The principal sources of asbestos in North America are Canada and Vermont. The ore generally contains 5 - lOt chrysotile, the remainder being rock of various types. The ore is crushed to release the chrysotile from1 the rock matrix, and the fibrous material is separated oy screening. Amosite and crocidolite are imported from Africa. 2) Background Levels of Asbestos - No data were found. 3) Commercial Uses of Asbestos - Most of the uses of asbesto'1 arise from its unique set of properties; fibrous nature, tensile strength (equivalent to piano wire), thermal and chemical stability. Uses of chrysotile include: cement reinforcement, insulation, ^ floor and ceiling tile, fire resistant building materials, textil^, paper, diaphragms for the electrolytic production of chlorine and^ many others. Crocidolite is used for the production of automatic^ err automobile transmissions. Total consumption of asbestos in the U.S. is about 800,000 tons annually. Dow uses for asbestos include insulation, filters, and diaphrams in chlorine cells. Plastic fabricators often use asbestos as a reinforcing agent in plastics. Asbestos 1972 - Cl C) ANALYTICAL CONSIDERATIONS Sampling techniques are critical for obtaining meaningful analyses of asbestos. The Environmental Protection Agency has recently prescribed a method of sampling air for asbestos. It involves collecting asbestos in air on a membrane filter and count ing the fibers greater than 5 micrometers in length at 400-450 X magnification (4 millimeter objective, phase contrast illumination). All crystalline forms of asbestos may be identified positively by their X-ray diffraction patterns. Electron miscroscopy and elemental analysis are also of assistance in establishing the identity and quality of the material. Differential Thermal Analysis has also been used in the identification of asbestos minerals. The Ecology Council is available for assistance in determining appropriate analytical methodology. ST0000896 Asbestos 1972 - Dl D) TOXICOLOGY 1) Animals - Two distinct diseases result from the inhalation of asbestos, (1) asbestosis, a fibrogenic disease of the lungs and (2) mesotheliomas, cancers of the lining of the chest and abdomen. A great many experimental studies have been carried out on laboratory animals in an effort to demonstrate the fibrogenic and tumorgenic properties of asbestos. Such experimental studies are complicated by many variables including the type and dimensions of the asbestos fibers administered; the contaminants present in the asbestos (e.g. trace metals and hydrocarbons); the route of administration; the species and strain of animal; the dosage; and the time following administration (latency period), a) Experimental Asbestosis Asbestotic pulmonary fibrosis (scarring of the lungs) has been produced experimentally in several species of animals, including rats, guinea pigs, hamsters, rabbits and monkeys. Zn these studies various modes of administration were used, the most frequent being inhalation, and single intratracheal or intra pleural injections. The slowly progressive diffuse pulmonary fibrosis observed in laboratory animals is considered to be the counterpart of the human disease. A striking feature in both animals and man is the very long latency period between exposure and evidence of the disease. Experimental asbestosis has been produced in one or more species by at least three foms of asbestos (chrysotile, aaosite, and crocidolite). The role, if any, played by various contaminants STOOOJ3897 Asbestos 1972 - D2 of asbestos (e.9. trace metals &-.i hydrocarbons) or fiber size, is not clear. b) Experimental Cancers Lung cancer has been produced experimentally in several species of animals (including rats, mice, and hamsters) by inhalation, or by single intratracheal or intrapleural injections of asbestos. Chrysotile has been the type of asbestos most frequently cited as the carcinogenic agent, however, other types of asbestos as well as contaminants (e.g. trace metals and hydrocarbons) have been implicated. Generally, the appearance of lung cancer has followed a long latency period, again, paralleling human experience. In view of the recent human experience, cancers (mesotheliomas) of the pleural surface (lining of the thoracic cavity) are of special concern. Such cancers have been observed in rats and hamsters several months after a single injection of the three most common types of asbestos (chrysotile, crocidolite, or amosite) into the chest cavity. Pleural and peritoneal mesotheliomas (cancers of the lining of the thoracic and abdominal cavities) have been observed in mice several months following the subcutaneous injection of crocidolite, amosite, or chrysotile. This study is of particular interest, since it provides evidence of migration of asbestos fibers. ST00Q0898 Asbestos 1972 - D3 c)Mutagenic and Teratogenic Effects There Is no evidence that asbestos is associated with mutagenesis or ceratogenesis. 2) Humans - At the present time, approximately five million workers in the United States are exposed to airborne asbestos in occupations involving the industrial production and use of asbestos-containing products. Epidemiological studies have shown that occupational exposures to all commercially used forms of asbestos have resulted In high rates of asbestos-related diseases! asbestosis, cancer of the lung, cancers of the lining of the thoracic and abdominal cavities, and other cancers. The present state of knowledge indicates that once exposure has occurred, asbestos-related disease may appear even though the exposure is discontinued. The disease may be evident after a latency poriod of 20 years or more; consequently, unless a very careful history is conducted the possible association with asbestos exposure may be missed. Recently, there ha3 been considerable alarm about asbestos exposure of the general population. The major potential for risk appears to lie in individuals with indirect occupational contacts, house hold contacts, or residence in the immediate neighborhood of asbestos sources. At presen*-. the significance and magnitude of nonoccupational exposures to asbestos are not resolved. ST0000899 Asbestos 1972 - 04 There are many variables in asbestos-related diseases that are not well understood. These include the duration, intensity and continuity of exposure (si; the specific type and dimensions of the asbestos fibers inhaled; the role of cofactors; the contaminants of the asbestos (e.g. trace metals and hydrocarbons) ; the presence of other concomitant dusts; the latency period; and individual idiosyncrasies. Many authors have emphasized the gravity of the asbestos hazard and the need for stringent controls, a) Pulmonary Asbestosis Asbestosis, the first recognized disease associated with the prolonged inhalation of asbestos (all types), is a disabling or fatal scarring disease of the lungs (progressive diffuse pulmonary fibrosis). The risk varies directly with the length of exposure and the dust concentration. The chief symptoms oft/) -H advanced asbestosis are a non-productive cough, shortness of CD breath, substernal chest pains, decreased chest expansion, ^ weakness, emaciation, clubbed finger tips, and curved finger- q O nails. X-ray findings show a fibrosis of the lung fields which is usually, but not exclusively, basilar, mid-lung field adhesions, pleural plagues and calcifications. b) Neoplasms from Inhalation of Asbestos Lung Cancer Many studies over the past twenty-five years have definitely confirmed an association between occupational exposure to Asbestos 1972 - 05 asbestos (all types) and a higher than expected incidence of lung cancer (bronchogenic carcinoma). The latent period between exposure to asbestos and evidence of lung cancer nay be even longer than for asbestosis; however, there is very little information on the dose-time relationship. While lung cancer is the most cannon complication of asbestosis, cases of lung cancer apparently induced by asbestos have been reported un accompanied by asbestosis. Cigarette smoking vastly enhances the chances of asbestos workers developing lung cancer. In view of the continued poor outlook following removal from exposure to asbestos, the dis continuance of cigarette smoking is a paramount prevention measure. C mcer of the Pleural and Peritoneal Surfaces Very little serious cc-.-.sideration was given to asbestos as an etiological factor in mesothelial malignancies prior to 1960. Since then, many reports have been published support - ig a -elationship between asbestos and pleural and peritoneal mesotheliomas. An outstanding feature has been the long period, commonly over 30 years, between the first exposure to asbestos and the appearance of a tumor. As with lung tumors, there is no good correlation between the severity of asbestosis and the occurrence of mesotheliomas. ST000090I T Asbestos 1972 - D6 There are some epidemiological data indicating that crocidolitc. and, to a much lesser degree amosite, produce mesotheliomas, wniie anthophyiiite ana chrysotne ao not; however, much more data are needed in this regard. Other Cancers Association between asbestos inhalation and malignancies of the gastrointestinal tract (stomach and colon) and other sites has been suggested. c) Neoplasms from Oral Ingestion of Asbestos Recently, controversial epidemiological evidence has been published indicating that the asbestos-contaminated talc on rice in the diet is the carcinogen or cocarcinogen responsible for the high incidence of Japanese stomach cancer. This opens up many areas of concern over the deleterious effect of orally ingested asbestos. Since asoestos-containing filter pads are commonly </> H used in the food and beverage processing industries, it is veryo O likely that many foods and beverages contain asbestos fibers. ^ In fact, asbestos fibers have been identified in beer and occur^ naturally in rivers when the water runs over asbestos containing0 rock. No doubt, there will be considerable research activity in this area in the immediate future. 3) Fish and Other Aquatic Organisms - No evidence has been found to indicate that asbestos is toxic to aquatic organisms No references Asbestos 1972 - 07 were found to studies of asbestos toxicity to aquatic organians. Bottom life could be affected if solids were to accumulate to the extent that the organisms become isolated from their normal environment, e.g., food sources, light, oxygen and pH. 4) Plants - No evidence has be*n found to indicate that asbestos is toxic to plant life. Accumulation of solids on foliage interferes with sunlight Availability for photosyntheses. 5) Biotransformation - Fiber siz is critically important in determining respirability, deposition, retention, and clearance from the pulmonary tract and is probably an important determinant of the site and nature of biological action. Little is known about the movement of fibers within the body, including their potential for entry through the gastrointestinal tract. ISi No data were found which indicate that asbestos is bioconcentratedH o or biomagnified. CD 3- o GO Asbestos 1972 - El E) ESTABLISHED STANDARDS 1) Air a) Occupational (1) The American Conference of Governmental Industrial Hygienists recommends the following Threshold Limit Value (TLV) as a time-weighted concentration for workmen exposed 7 to 8 hours per day, 40 hours per week. Asbestos (all types) 5 fibers/ml >5j* in length as determined by the membrane filter method at 400-450 X magnification (4 mm objective) phase contrast illumination. Concentrations 5 fibers/ml but not to exceed 10, may be permitted for 15 minute periods each hour up to five times daily. ST000090U (2) The British Occupational Hygiene Society recommended the / following criteria for limiting exposure to chrysotile v asbestos assuming a 1% risk of contracting asbestos disease . during a 50 year working exposure. Dust Category Chrysotile concentration* Fibers/ml**___________ ____ Negligible Low Medium High <0.5 0.5-2.0 2-10 > 10 *Averaged during a three-month period **Greater than 5VJ in length. Asbestos 1972 - E2 From these criteria, a limit of 100 fibers/ml-years was proposed, hence a limit of 2 fibers/ml averaged over a 50year period. (3) The National Institute of Occupational Safety and Health (NIOSH) has recoanended to the Labor Department that the Occupational Safety and Health Regulations by the Labor Department be amended within two years and prescribe a limit of no more than 2.0 asbestos fibero/ml of air based on a count of fibers greater than 5y in length, determined as a time-weighted average exposure for an 8-hour work day, and no peak concentration to exceed 10.0 fibers determined by a minimum sampling time of 15 minutes. The two-year delay is to allow time for the installation of necessary engineering control. In addition, medical surveillance will be required. b) Ambient Air Quality - No numerical standards for asbestos have been found. However, the U. S. Environmental Protection *. Agency has proposed ;n 40 CFR Part 61 that "no visible dust" will be the criteria and control will be based on elimination at the source of emission. c) Emission Levels - The U. S. Environmental Pro' -sction Agency has proposed the limitation of all airborne asbestos by re quiring suitable collection devices for the airborne asbestos on all operations that may generate airborne asbestos. Suitable collection devices are specified (40 CFR Part 61.23 & .24). ST0000905 Asbestos 1972 - E3 2) Water a) Potable - Neither the U.S.P.H.S. nor any other group appears to have set a standard for asbestos In drinking water. b) Stock and Wildlife - No standards have been found. c) Aquatic Life - No standards have been found. d) Irrigation - No standards have been found. e) Industrial Effluent -No standards have been found. 3) Soil - No standards have been found. 4) Pood, Drugs and Food Additives - No standards have been found. f ST0-000906 Asbestos 1972 - Fl F) CONSIDERATIONS FOR ESTABLISHED GUIDES FOR A GIVEN LOCATION 1) Inhaled asbestos is a potent carcinogen. It has been receiving such attention lately. Seme scates have banned certain uses of asbestos including the spraying of insulating material in building construction. 2) Orally ingested asbestos in water or food is now under scrutiny as a possible causative factor in cancer of the gastrointestinal tract. 3) The effect of asbestos on aquatic life has not been studied. 4) The goal should be to avoid the exposure of all individuals to asbestos dust since the actual no-effect level is still unclear. \dequate control methods must be implemented. Stringent medical follow-up studies on these asbestos workers will be required. 5) Due to lack of knowledge of the effects of asbestos in water, and the possible emotional factor associated with potential carcinogens, discharge to the water environment should be minimized. . ST0U00907 6) Cigarette smoking vastly enhances the chances of asbestos workers developing lung cancer. Asbestos 1972 - Gl G) SUGGESTED DOW GUIDES All local and national regulatory requirements must be met. The followir.g guides should be used in the absence of such regulations or if the Dow Guide is lower than the legal requirements. 1) Total Plant Emissions - Less than 0.01 kg/day total emission of asbestos to air as finely divided asbestos may present a health hazard in certain local situations. Release to soil in such a way that there is no possibility of asbestos becoming airborne presents much less of a problem. 2) Air a) Occupational - Time-weighted average concentration for repeated 8-hour period, 40 hours/weekj Asbestos (all types) 2 fibers/ml of air based on a count of fibers >5y in length, with peak concentrations not to exceed 10 fibers/ml ot air as determined by a minimum sampling time of 15 minutes, and using the membrane filter method of collection and analysis at 400-450 X magnification (4 mm objective) phase contrast illumination. In addition, medical surveillance will be recuired for those employees who are exposed to asbestos at timeweighted average levels greater than 1 fiber/ml of air or ;)eak concentrations greater than 5 fibers/ml of air. 80600001S Asbestos 1972 - G2 b) Ambient Air Quality - Averag-sd over a 24-hour period: Asbestos (all types) - 0.1 fibers/ml of air >5y in length as determined by the EPA method. c) Emission - Emission must be controlled so that all ambient guides are met. In addition there are limitations on the uses and criteria for emission controls for asbestos stipulated by the Environmental Protection Agency in the Code of Federal Regulations, Title 40, Part 61, Subpart B. 3) Water - Asbestos must be considered in the limit for total suspended solids of IS mg/1. There is at the present time no other basis to establish a specific standard. 4) Soil - Asbestos may be disposed of in landfill areas, but it must be done in a manner such that it cannot become resuspended in air. 5) Food, Drug3 and Food Additives - Contamination of foods, drugs and cosmetics with asbestos must be avoided. ST0000909 - Asbestos 1972 - HI H) PRIME REFERENCES 1) Water Ouality Criteria. Report of the National Technical Advisory Committee to the Secretary of the Interior. Fuer.-*l Water Pollution Control Administration (1968) 2) Industrial Toxicology, 2nd Edition L. T. Fairhall Hefner Publishing Co., New York (1969) 3) Threshold Limit Values of Airborne Contaminants and Intended Changes Adopted by American Conference Governmental Industrial Hygienists for 1970 American Conference Governmental Industrial Hygienists 1014 Broadway, Cincinnati, Ohio (1970) 4) Documentation of the Threshold Limit Values, Third Edition American Conference Governmental Industrial Hygienists 1014 Broadway, Cincinnati, Ohio il971) The Diseases of Occupations, Fourth Edition Donald Hunter Little, Brown and Company, Boston (1969) 0 1600001S 6) Airborne Asbestos - A Report prepared by the Committee on Biological Effects of Atmospheric Pollutants National Academy of Sciences, National Academy of Engineering, Washington, D. C. (1971) (Available from National Technical Information Service, Springfield, Virginia PB 198-581) k. 7) Background Information - Proposed National Emission Standards for Hazardous Air Pollutants: Asbestos Environmental Protection Agency i Office of Air Programs, Research Triangle Parle, N. C. (December 1971) Office of Air Programs Publication No. APTD 0753 ! I 8) Preliminary Air Pollution S of Asbestos - A Literature Review R. J. Sullivan and Y. C. Anthanassiadis U. S. Department HEW, National Air Pollution Control Administration, Publication No. APTD 69-27 (1969) *